Category Archives: Ocean sediment

Hiding the Decline: MD01-2421

As noted in my previous post, Marcott, Shakun, Clark and Mix disappeared two alkenone cores from the 1940 population, both of which were highly negative. In addition, they made some surprising additions to the 1940 population, including three cores whose coretops were dated by competent specialists 500-1000 years earlier. While the article says that ages […]

The Marcott-Shakun Dating Service

Marcott, Shakun, Clark and Mix did not use the published dates for ocean cores, instead substituting their own dates. The validity of Marcott-Shakun re-dating will be discussed below, but first, to show that the re-dating “matters” (TM-climate science), here is a graph showing reconstructions using alkenones (31 of 73 proxies) in Marcott style, comparing the […]

The Trouet Ocean Proxies

Here are the ocean proxies used in Trouet et al. As usual in Team studies, it is a total mystery how they are selected. Trouet et al is a bit different from usual Team studies in that it argues for a MWP-LIA global reorganization, something that I’ll get to soon. Today, I want to chat […]

More Z-Score Opportunism

We’ve frequently observed that the reduction of data to standard deviation units (z-scores) is often associated with seemingly opportunistic orientation of the data sets. Often this is buried in the multivariate methodology. Principal components and RegEM can both function to opportunistically provide orientations to “proxies”. In Mann 2008, we saw pretty examples of proxies being […]

Loehle Proxy MD95-2011

One of Loehle’s proxies – the one that ends in the 16th century – has occasioned some interest and I took some time to investigate it. It is an alkenone SST estimate from ocean sediment core MD95-2011 from the Norwegian Sea (66 58.19N, 07 38.36E and 1048 m). The series ends in the 16th century […]

ABC: Global warming puts fish stocks at risk

While trawling for high-resolution ocean sediment cores, I noticed an interesting core offshore Morocco, reported by McGregor et al (Science 2007) earlier this year. This study was released just prior to IPCC complete with press release. Can’t we all think back to a quieter time when a scientist having labored to produce a detailed analysis […]

Donnelly and Woodruff 2007

Richard T and I had an interesting discussion here about the bioturbation and coarse fractions in the Arabian Sea G Bulloides proxy that is very influential in Moberg and not used in Loehle (as it was not calibrated to temperature.) I had observed that the increase in G Bulloides percentage in the very top part […]

David Black, Cariaco and Prompt Archiving

David Black and associates have just (Oct 2007) published a new paper showing a reconstruction of SST from Cariaco sediments using Mg-Ca for the period 1221-1990 (thanks to Eduardo Zorita for alerting me to the study.) In this case, I am happily able to report that the relevant data was archived at WDCP contemporary with […]

A Coarse Fraction Bias in Arabian Sea G Bulloides?

In our recent discussion of the Arabian Sea G Bulloides series, I noticed a remarkable increase in the coarse fraction percentage in the top 1.3 cm of the critical RC2730 core. Willis has also commented on this. In core 2730, there is a correlation of 0.91 between the fraction of coarse particles and the percentage […]

The Arabian Splice

One of the reasons why scientists have been so quick to use tree ring information despite all the problems is that, for the most part, there is excellent dating control on tree ring chronologies, something which can be problematic in other proxies. Today I want to document some notes on dating the Arabian Sea G […]


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